Field of the Invention
The present invention is directed in general to semiconductor devices and methods for manufacturing same. In one aspect, the present invention relates to the fabrication of semiconductor devices or integrated circuits with optical micro-electro-mechanical systems (MEMS) circuits and devices.
Description of the Related Art
In information systems, data signal information is communicated between devices and circuits using different types of signal connections. With electrical conductor-based connections, such as conventional wires or through silicon vias (TSVs), there are power and bandwidth constraints imposed by the power requirements and physical limitations of such conductor-based connections. For example, stacked die modules have been proposed to provide high density information systems, but the power consumption and associated heat dissipation requirements for communicating data signals between stacked die modules using conductor-based connections can limit the achievable density. In addition, the bandwidth of such stacked die modules is limited by the number and inductance of TSVs and other conductor-based connections for such die stacks. To overcome such limitations, optical communication systems have been developed as a way of communicating at higher bandwidths with reduced power. With such optical communication systems, a monochromatic, directional, and coherent laser light beam is modulated to encode information for transfer to other devices or circuits of the system, typically by transferring modulated light signals along an optical fiber or waveguide path. Unfortunately, there are alignment challenges with using optical waveguides to transfer optical information between different integrated circuit (IC) chips in a system in terms of cost, complexity, and control requirements. These challenges arise from the tight alignment tolerances required to meet information transmission requirements and other use factors that can disrupt alignment during device operation. Attempts have been made to overcome these challenges by using external mirrors or deflectors to optically transfer information across free-space between different IC chips present their own difficulties, costs, and control requirements. For example, the optical transmitter, deflector structures, and the optical receiver not only impose additional costs and complexity, but must also be aligned to ensure a desired level of information transmission. In addition, alignment errors can be introduced by the system assembly process, as well as vibration (e.g., dropping) or temperature changes during use. For example, components of an optical link may become misaligned if a cell phone or notebook computer is dropped on a surface. Furthermore, the cost for designing and assembling components that are precisely aligned may be cost prohibitive. Finally, control circuits and external signal deflection structures can increase the overall system complexity, thereby reducing possible signal bandwidth between different IC chips. As a result, the existing solutions for transferring modulated light signals along optical waveguide paths and between different IC chips make the implementation of high bandwidth optical interconnects extremely difficult at a practical level.
It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the drawings have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements for purposes of promoting and improving clarity and understanding. Further, where considered appropriate, reference numerals have been repeated among the drawings to represent corresponding or analogous elements.